1. Technical Field
The present invention relates to an ultrasonic transducer that sends and/or receives ultrasonic waves, as well as a biological sensor equipped with said ultrasonic transducer, and a method for manufacturing said transducer.
2. Related Art
An ultrasonic transducer that sends and receives ultrasonic waves has been known before now (see Japanese Laid-Open Patent Application Publication No. 2003-304595, for example).
The diaphragm-type transducer (ultrasonic transducer) discussed in the above mentioned publication comprises a silicon substrate in which an opening is formed, an insulating layer and vibrating layer laminated on this substrate so as to block off this opening, and a piezoelectric element that is laminated over the vibrating layer and consists of a lower electrode, a piezoelectric thin-film, and an upper electrode. This ultrasonic transducer is formed by laminating the insulating layer, the vibrating layer, and the piezoelectric element on the upper side of the substrate, and then etching from the lower face of the substrate down to the insulating layer.